Kent Fredric <[email protected]> writes:
> On 26 January 2016 at 12:02, Nathan Hilterbrand <[email protected]> wrote:
>> return wantarray() ? ($a, $b) : [$a, $b];
>>
>> In a list context, you get back a list.. otherwise you get back a reference
>> to a list. Might not be what you want, though.
>>
>> Works with arrays, too..
>>
>> my @anarray = (....)
>> return wantarray() ? (@anarray) : [@anarray];
>
>
> I've found pretty much everywhere you'd want that its simpler to just
> return either [@anarray] or just \@anarray
>
> Returning lists is cute and all, and returning lists only when in list
> context is cute ...
>
>
> But in practice I find it mostly painful, because you find yourself
> needing to "trick" perl into thinking its in list context from time to
> time.
>
> And even occasional use of
>
> return (()= function() )
>
> Or whatever the right magic is to force the called function into list
> context is just more pain than its worth.
>
> It just seems more practical to always return scalar return values of
> some description.
>
> Now, if you want a more useful application of the comma operator, consider:
>
> while ( condition ) {
> $x = function(), next if $second_condition
> }
That's convoluted code to me. If I could read that, I'd read it as
while ( $condition ) {
$x = function();
next if $second_condition;
}
>
> Which is equivalent to
>
> while ( condition ) {
> $second_condition and $x = function(), next;
> }
>
> Which is similar to
>
> while( condition ) {
> if ( $second_condition ) {
> $x = function();
> next;
> }
> }
That is different from the above. If you need it in one line:
while ( $condition ) {
next unless($second_condition); $x = function();
}
> But allows a more compact representation ( which matters if you have a
> dozen or so such conditions ),
> and avoids adding a lexical scope.
You could write
while ( $condition ) { $x = function(); next if $second_condition; }
instead. I like lexical scopes.
But what did you actually want in your first example? This
> while( condition ) {
> if ( $second_condition ) {
> $x = function();
> next;
> }
> }
or that
while ( $condition ) {
$x = function();
next if $second_condition;
}
?
> ( Fun fact, replace "$x =
> function(), next;" with "do { $x = function(); next }" and watch
> deparse turn it back into an "if" statement :) )
>
> But you can't use "&&" or "and" in the expression, because
> "function()" could return a false value, which would prevent the
> 'next' occurring.
Perhaps you could also use brackets, like
while ( $condition ) {
(($second_condition and ($x = function())), 1), next;
}
for whatever that would do.
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